The STPM01 is designed for effective measurement of active, reactive and apparent energy in a power line system using Rogowski coil, current transformer and shunt sensors. This device can be implemented as a single chip monophase energy meter or as a peripheral measurement in a microcontroller based monophase or 3-phase energy meter. The STPM01 consists, essentially, of two parts: the analog part and the digital part. The former, is composed by preamplifier and 1st order Δ Σ A/D converter blocks, band gap voltage reference, low drop voltage ulator, the latter, is composed by system control, oscillator, hard wired DSP and SPI interface.